<style>
    .item1{background:LightSkyBlue;}
    .item2{background:LightSalmon;}
    .item3{background:PaleTurquoise;}
    .item4{background:LightPink;}
    .item5{background:PaleGreen;}

    .container {
        font-size: 40px;
        min-height: 100px;
        width: 100%;
        background: LightGray;
        display: grid;
        /* 请修改本行以下的代码 */

        grid-template-columns: repeat(auto-fill, minmax(60px, 1fr));

        /* 请修改本行以上的代码*/
        grid-template-rows: 1fr 1fr 1fr;
        grid-gap: 10px;
    }

    .container2 {
        font-size: 40px;
        min-height: 100px;
        width: 100%;
        background: Silver;
        display: grid;
        grid-template-columns: repeat(3, minmax(60px, 1fr));
        grid-template-rows: 1fr 1fr 1fr;
        grid-gap: 10px;
    }
</style>
<div class="container">
    <div class="item1">1</div>
    <div class="item2">2</div>
    <div class="item3">3</div>
    <div class="item4">4</div>
    <div class="item5">5</div>
</div>
<div class="container2">
    <div class="item1">1</div>
    <div class="item2">2</div>
    <div class="item3">3</div>
    <div class="item4">4</div>
    <div class="item5">5</div>
</div>